1. Field of the Invention
The present invention relates generally to the field of medical systems, and more specifically to managing reliable, high availability communications for wireless medical devices.
2. Description of the Related Art
Traditionally, medical system products transmit control signals over a fixed wire or cable. Current advancements in wireless communications techniques, including short-range radio and light wave technology, enable designers to employ wireless connections to transmit control signals and other data, thus removing the need for a traditional fixed wire or cable. Examples of removable or non-fixed devices include monitors or monitoring equipment, test equipment, remote control devices, and so forth.
The rapid advancement and proliferation of short-range radio technology affords medical system product designers and manufacturers the ability to create and deploy non-fixed subsystems and devices without need for a conventional fixed physical communication cable. For example, non-fixed devices meeting or complying with the Institute of Electrical and Electronics Engineers (IEEE) 802.11g and Ericsson Bluetooth™ specifications provide short-range radio technology to enable for wireless communications. These technologies allow for wireless transmission of signals over short distances between computers and other electronic devices. Bluetooth™ enabled devices are capable of an approximate 10-meter transmission range at data rates up to 720 kilobits/sec, and can provide better security features than devices implementing IEEE 802.11g communications.
Although typically not well suited for medical applications, line-of-sight wireless light wave technology, including Infrared Data Association (IrDA) techniques, may also be employed by product designers to realize wireless connections.
Implementing either the Bluetooth™ or IEEE 802.11g specifications will yield a communications path between wireless non-fixed devices and subsystems. Each specification also addresses providing an interference resistant communications path with automatic error detection and correction capabilities for transmitting and receiving of control signals, data, and information.
However, the Bluetooth™ and IEEE 802.11g specifications only address the wireless transmission and reception of data, control signals and information across a single communications path. Non-fixed wireless medical subsystems and devices require a continuous, reliable, and high availability communications network to ensure uninterrupted operation of an instrument host system. The above-cited specifications do not provide for a continuous, reliable, and highly available communication experience under all operating theater conditions. Due to the critical health support requirements for medical equipment and the potential catastrophic consequences of a communications connection failure in such equipment, effective deployment of medical systems incorporating wireless devices require a highly reliable communications management scheme to ensure a reliable connection from the instrument host system is constantly available to fielded non-fixed wireless subsystems and devices. Neither of the foregoing specifications guarantees this high a level of reliable communications management.
Active wireless medical devices, when used under normal operation, are exposed to numerous sources of electrical and magnetic interference, environmental conditions, and reliability issues. Electrical and magnetic interference may cause a loss of signal strength or degrade the signal quality sufficient to cause a wireless communications path to disconnect. For example, a single wireless Bluetooth™ connection requires a few seconds to re-establish a failed connection. During this reconnect time period, the surgeon can lose remote control of the surgical system and be unable to control the medical equipment. This reconnection time delay is not desirable or suitable for safety critical devices or equipment. footpedal. In addition, a “zero position switch” footpedal incorporates the ability to detect the footpedal returning to a non-active state independent of the linear position detection, thus serving as a fail-safe trigger. If this independent fail-safe trigger is directed through a single wireless channel, communication of this trigger is subject to a single-point-of-failure arrangement that loses any redundancy benefit.
Reliable wireless device communication management schemes in this environment must therefore not only provide a reliable continuous communications path but also a mechanism for monitoring and reporting the signal strength and signal quality condition for wireless subsystems and devices when subjected to external interference and environmental conditions found in the operating theater.
Thus it would be advantageous to offer an architecture and design that provide wireless operated subsystems and devices a reliable and highly available communications management scheme to ensure safe and continuous peripheral product operation in an environment where the wireless device and controlled instrument host are subjected to conditions that may interfere with the communication path.